"GLOBAL_REMOVED_IF_UNREFERENCED" must never be used with an "extern" declaration. It can only be used with the declaration of the actual global variable.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@6241 6f19259b-4bc3-4df7-8a09-765794883524